Unitary high pressure slip seal cartridge

ABSTRACT

A unitary cartridge seal assembly for a high pressure liquid sealing connection between two relatively rotatable liquid passage members of a rotary nozzle or a swivel and a tool having such an assembly. The assembly comprises a thimble shaped or cylindrical housing having a flanged retainer fitting within an axial orifice to hold the components together while allowing sufficient axial movement to insure complete sealing of the respective elements. The assembly provides “drop-in” replacement of wearable parts of the rotary face seal of a high pressure water jet blasting tool.

This application claims the benefit of provisional application No.61/011,342 filed Jan. 15, 2008.

This invention relates to simplification of the replacement of wearingparts of seals between two relatively rotatable devices having connectedhigh pressure liquid passages.

BACKGROUND OF THE INVENTION

In the field of high pressure rotary liquid handling devices operatingparameters can exceed 10,000 psi, rotating speeds of 1,500 rpm and flowrates of 25 gpm. Accordingly the rotary seals required to work undersuch constraints generally require careful and precise assembly of therelative moving parts. An example of such a seal is shown in applicant'sprior U.S. Pat. No. 6,059,202 (Zink et al) which is incorporated hereinby reference.

Rotary face seals as used in such devices may incorporate numerousrelatively small parts. While the mating portions of the rotating sealsare relatively simple and inexpensive, they may require some degree ofprecision of assembly to function properly. Since these parts aresubject to wear in use they require regular replacement as a part ofnormal maintenance. Such high pressure rotary cleaning tools arecommonly used for cleaning or descaling of industrial equipment, forexample boilers, where downtime of can result in substantial expense.Accordingly, the maintenance of the cleaning tools typically will takeplace in the field under less than pristine conditions and by unskilledpersonnel.

SUMMARY OF THE INVENTION

The present invention provides a cartridge assembly comprising thewearable parts of a rotary face seal for use in a high pressure rotarywaterjet tool. The cartridge is positioned within and at the inlet endof the tool and is readily accessible and removable through the openingused to provide a supply of operating fluid. The seal cartridge ispre-assembled as a “drop-in” unit to facilitate routine maintenance yetprovides for sufficient relative movement between components within thecartridge and between the cartridge and tool to insure complete sealingof the liquid path.

Among the objects of the invention is to simplify the replacement ofwearing parts of a small high pressure spray nozzle seal to facilitatereplacement of the wearable parts.

Another object of the invention is to minimize the time required toreplace wearing parts of a rotary face seal in a high pressure waterjettool.

Another object of the invention is to insure the accuracy of assembly ofwearing parts when such parts are replaced in the field.

Another object of the invention is to provide a single assemblycontaining all the wearing parts for small diameter rotating highpressure spray nozzle.

Another object of the invention is to provide an inexpensive assemblycontaining all the wearing parts for small diameter rotating highpressure spray nozzle.

Another object of the invention is to provide simple access to all thewearing parts for small diameter rotating high pressure spray nozzle.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of the high pressure face sealcartridge of the preferred embodiment.

FIG. 2 is an exploded view of the components of the high pressure faceseal cartridge of FIG. 1.

FIG. 3 is a cross sectional view showing the high pressure face sealcartridge of FIG. 1 in place in a representative high pressure rotarycleaning tool.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The cartridge assembly of the preferred embodiment as shown in FIG. 1 isadaptable to use in any high pressure rotary device having relativelyrotatable elements such as the main body or housing B and shaft C shownin the representative tool of FIG. 3. The cartridge A is positionedwithin and at the inlet end of the tool and is readily accessible,insertable and removable through the axial opening E used to provide asupply of operating fluid. The seal cartridge A is held in place by asimple O-ring 11 which provides simple retention of the cartridge whenthe tool is non-operational or detached from a source of operating fluidsuch as a hose or similar fluid line. Such a hose, when attached, isthreaded into inlet nut 12 thereby fully securing the cartridge inplace.

The seal assembly A is contained within a generally thimble-shaped outerhousing 1 preferably machined of an appropriate grade of stainless steelor other similarly suitable material. A small diameter outer portion 20of flanged seat cap or retainer 2 extends through an opening or orifice30 in the housing 1. Orifice 30 has a diameter corresponding closely tothe small diameter 20 of retainer 2. The diameter of inner flangeportion 21 of cap 2 is larger than the diameter of orifice 30. Retainer2, having an external sealing face 22, is preferably formed fromgall-resistant stainless steel to minimize problems resulting from somemovement which may occur between the cap and the respective matingportion of the swivel tool shaft such as C in FIG. 3. The flangedconfiguration thereby allows the cap (a) to freely rotate within thehousing while retaining the integrity of the cartridge assembly,particularly prior to the cartridge being installed in the rotary tool,and (b) to have some limited axial movement to insure secure mating andsealing of the faces of the respective components which comprise thefluid path as described further below. The seat cap is provided with aflat face 22 to seat against and mate with a corresponding face 92 onone end of a rotatable shaft such as that shown as C in FIG. 3. Theflanged seat cap 2 receives an annular seat 3 which is made of tungstencarbide or similar wear resistant and durable material. Seat 3 providesa smooth flat face at 34 where the relative rotary movement between seat3 and seal 4 occurs. The annular seal 4 has an external diametermatching that of inlet seat 9 and is made of an extrusion-resistantcross-linked ultra-high molecular weight polyethylene or other similarmaterial having the characteristic of providing a relativelylow-friction flat seal surface at the interface 34 with seat 3. Seat 3is rotatably retained within annular carbide seal retainer 4 having acentral bore corresponding in diameter to the external diameter of seat3. In use and under pressure of the operating fluid the outer surface ofseal 6 is forced tightly against the inner diameter of seat 9 and isfurther sealed by O-ring 8. The inner cylindrical surface of insert seat9 extends longitudinally over the entire length of seal 6.

A thimble shaped stainless steel seal support 7 fits within seal 6 toprevent any folding or undesirable deformation of seal 6. In use, afluid supply is provided through a connector threaded into in the inletend E of the exemplary tool shown in FIG. 3, also securely fixing thecartridge assembly A in place. Thus cap 2, seat 3 and seal 6 are kept inclose sealing contact to maintain the continuity of the path of flow ofthe operating fluid. O-ring 5 provides an annular seal between holder 4and 15 retainer 9. O-ring 10 fits within a groove in the inner wall ofhousing 1 and abuts a face of retainer 9 to retain or hold allcomponents in place within housing 1 when the swivel is not attached toa fluid supply.

The respective components cap 2, seat 3, seal 6 are each provided with acommonly sized axial bore corresponding to the axial bore of shaft C toconduct the high pressure operating fluid along the axis of the tool tothe head D where the high pressure fluid is discharged through nozzlessuitable for the intended application. As shown, cap 2 and seat 3 remainfixed with respect to one another and rotate in direct synchronizationwith shaft C while all other cartridge components remain fixed withrespect to one another and with main body B. Accordingly as used herein,face sealing between respective components is “fixed” or “static” wherethe components have no intended relative movement. Where the componentsrotate relative to one another the seal is “movable,” “rotatable” or“dynamic.”

1. A unitary cartridge seal assembly for a high pressure liquid sealingconnection between two relatively rotatable liquid passage members of arotary swivel tool, comprising, a housing, a seal and a seat containedwithin and coaxially oriented with respect to said housing, said sealand seat being in sealed rotatable engagement when said assembly issecured within a rotary swivel tool, said assembly having one or moreretention elements to maintain the integrity of the assembly when itsaid assembly not secured into a rotary swivel tool,
 2. A unitarycartridge seal assembly according to claim 1 wherein said housingcomprises a thimble shape having a central axis, an inlet end and anoutlet end, providing an axial liquid path through a seal, a seat and aretainer within said housing, said seal element is retained coaxiallywithin said housing toward said inlet end of said housing, said a seatis retained coaxially within said housing and has a first enddynamically sealed against said seal and a second end statically sealedagainst said retainer,
 3. A unitary cartridge seal assembly according toclaim 2 wherein said retainer is flanged and is coaxial with and passesthrough said housing orifice, said retainer includes a first outerportion having a diameter axially movable within said orifice and asecond inner portion having a diameter larger than the orifice diameterto prevent axial movement of said retainer through said orifice,
 4. Aunitary cartridge seal assembly according to claim 3 wherein saidretainer has a is flanged and is coaxial with and passes through saidorifice, said retainer includes a first outer portion having a diameteraxially movable within said orifice and a second inner portion having adiameter larger than the orifice diameter to prevent axial movement ofsaid retainer through said orifice,
 5. A unitary cartridge seal assemblyaccording to claim 1 wherein said at least one said retention element isan O-ring.